154 



LEAVES 



FIG. 66. 



erect habit and notice the position of the leaves with 

 reference to the stem on which they grow. 



Now bend a branch over and 

 weight it so that it will occupy 

 as nearly as possible a horizontal 

 position. 



After a few days remove the 

 weight and bring the branch back 

 into its original position. What 

 is the position of the leaves now? 

 How do you account for this 

 change ? Observe the same branch 

 again after another week. What is the position of the 

 leaves now ? (See Ex. 149.) 



Compare erect with drooping branches on deutzia, snow- 

 ball, and other garden shrubs. 



135. LEAVES 

 Object. To study the direction of growth. 



Select a young vigorous sunflower plant growing in a 

 flowerpot. A plant having four or five leaves is a con- 

 venient one for the purpose. 



Lay the flowerpot on its side between two blocks. (1) 

 Make a sketch of the plant. (2) After an hour or two 

 observe the plant. Note any change of position in leaf or 

 stem and sketch it again. (3) Continue making observa- 

 tions and sketches until the stem has assumed a vertical 

 position. 



Which responded to the change of position, leaf or stem ? 

 Which part of the stem was first to change its position? 

 What leaves were first affected? Which last? Which, 

 if any, not at all ? 



